The Order of Saint John of Jerusalem, also known as the Knights of Malta, is celebrating its 900th anniversary.

The Order of Saint John of Jerusalem was founded as a crusading Christian military order in the 11th century and transformed its mission several times over the intervening centuries. This military order engaged in holy war against the Saracens and later the Ottoman Turks in the Levant and across the Mediterranean. The Order has successively been based in Jerusalem, Cyprus, Rhodes, Malta, and now Rome.

The Knights of Malta held a procession in the Vatican City today and attended mass at Saint Peter’s Basilica.